This water pump seal ring sits between the water pump shaft and the engine block, preventing coolant leakage from the pump housing. It maintains the seal around the rotating shaft as the pump circulant passes through the engine cooling system. A worn seal ring allows coolant to weep past the shaft, leading to gradual coolant loss and potential overheating. This original AGCO component is machined to the same face flatness and spring tension as the original assembly, so the seal face mates correctly with the pump impeller without requiring shimming or adjustment. On reinstall, replace the pump gasket and torque the mounting bolts to specification.